textproduct: Rapid City

KEY MESSAGES

- Elevated to near critical fire weather conditions on Sunday.

- Warm (above average) temperatures on Sunday.

- Gusty westerly winds of 25 to 35 mph and gusts of 50 mph on Sunday across northwestern South Dakota.

- Cooler Monday through Wednesday.

DISCUSSION

(This Evening Through Saturday) Issued at 1217 PM MST Sat Mar 7 2026

Upper level analysis shows a positivity tilted upper trough stretching from Hudson Bay through the Central Plains down to the Baja Peninsula. High pressure over the eastern Pacific is squeezing the trough eastward as it builds into the Pacific Northwest and northern Rockies. This is resulting in northwest flow across the forecast area. At the surface, a weak trof extends from a low in eastern Alberta down through central Montana into central Wyoming while high pressure sits over the central Rockies in Wyoming, Utah and Colorado. Satellite imagery has clear skies across the forecast area with mid and high clouds approaching the area from the west and northwest.

For this afternoon, the mid and high clouds will overspread the area by evening. Westerly winds will increase across northwestern South Dakota and portions of northeastern Wyoming and far southwestern South Dakota. Sustained winds of of 18 to 25 kts will be common in the winder areas as gusts approach 40 kts. Though gusts will be marginal for wind advisory criteria, have decided to forgo an advisory as it will be limited in area and will be in the "usual" windy areas.

For this tonight, clouds will remain over the area before decreasing around sunrise. Westerly/southwesterly winds will subside a little overnight, but the upper flow and cloud cover will assist in keeping temperatures 10-20 degrees above average overnight.

Sunday will be warm as the upper trough moves to the east coast and weak ridging overtakes the area. Zonal upper flow with warm air being pushed into the region will result in high temperatures in the mid 60s to mid 70s, which are 25 to 30 degrees above average. Gusty westerly winds of 25 to 35 mph and gusts up to 50 mph will be common across portions of northeast Wyoming and the western South Dakota Plains. These wind speeds reach wind advisory criteria, therefore have issued a wind advisory for northwestern South Dakota for Sunday. Due to dry fine fuels and grasses, there is also a fire danger threat. Minimum relative humidity is around 25 percent in locations with greater wind speeds, but lower around the I-90 corridor where wind speeds will be less. Regardless, very high to extreme grassland fire danger is expected. Will hold off on a Red Flag Warning at this time as the relative humidity doesn't quite reach criteria of lower than 15 percent for 3-hours or more with winds/frequent greater than 25 mph. However, will be highlighting the very high to extreme grassland fire danger.

On Monday, the upper flow turns more zonal across the northern half of the CONUS and a cold front moves through the forecast area. Several weak impulses in the flow and a developing shortwave trough swings through Tuesday night and Wednesday and back to northwest flow by Friday as the jet stream is positioned over the area. All of this will result in near daily precipitation chances, for light precipitation, and breezy to windy conditions most days. Ensemble model solutions seem to hint this

AVIATION

(For the 00Z TAFS Through 00Z Sunday Evening) Issued At 331 PM MST Sat Mar 7 2026

VFR conditions are expected through the forecast period. Breezy west to northwest winds are expected overnight through Sunday.

FIRE WEATHER

Issued At 1217 PM MST Sat Mar 7 2026

Elevated to near critical fire weather conditions this weekend. For this afternoon, snow-free locations across the plains will have very high to extreme fire danger. Minimum relative humidity values will fall to around 20 percent and westerly winds of 15 to 25 mph will be common. Stronger winds and slightly lower relative humidity will be common on Sunday with warmer temperatures. Extreme grassland fire danger on Sunday will be common across most of the lower elevations in the forecast area. Criteria for Red Flag Warnings require lower relative humidity than the current forecast, thus will highlight fire danger as a grassland/rangeland threat considering the winds will be the strongest on the plains.

UNR WATCHES/WARNINGS/ADVISORIES

SD...Wind Advisory from 9 AM to 6 PM MST Sunday for SDZ001-002-012- 013-078. WY...None.